diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index 7b7a551fb32d03b1e23766d6761f02b77d033491..91352ed4f3cb144784ebf6ea2cd15233b5970d19 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -6572,7 +6572,9 @@ void LLPipeline::renderDeferredLighting()
 		if (LLViewerShaderMgr::instance()->getVertexShaderLevel(LLViewerShaderMgr::SHADER_DEFERRED) > 2)
 		{
 			mDeferredLight[1].bindTarget();
-			// clear color buffer here?  doesn't seem to matter.
+			// clear color buffer here (GI) - zeroing alpha (glow) is important or it will accumulate against sky
+			glClearColor(0,0,0,0);
+			mScreen.clear(GL_COLOR_BUFFER_BIT);
 		}
 		else
 		{